How can you extend the Bitmap class

Question

I am trying to extend the Bitmap class so that I can apply my own effects to the image. When I use this code:

namespace ImageEditor
{
    public class Effects : System.Drawing.Bitmap

    {
        public void toBlackAndWhite()
        {
            System.Drawing.Bitmap image = (Bitmap)this;
            AForge.Imaging.Filters.Grayscale filter = new AForge.Imaging.Filters.Grayscale();
            this = filter.Apply(this);
        }
    }
}

I get the following error:

'ImageEditor.Effects': cannot derive from sealed type 'System.Drawing.Bitmap'

So, is there a way around this or is it just impossible to extend the class?

Thanks.

Answer 1

You cannot get from Bitmap because it is sealed.

If you want to add a method to the Bitmap class, write an extension method:

// Class containing our Bitmap extension methods.
public static class BitmapExtension
{
    public static void ToBlackAndWhite(this Bitmap bitmap)
    {
        ...
    }
}

Then use it like this:

Bitmap bitmap = ...;
bitmap.ToBlackAndWhite();

Answer 2

+1 for Judas answer.

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Answer 3

BitmapSource, WPF, toblackandwhite - WPF . . BitmapSource

Answer 4

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Answer 5

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If you really intended to override some of the Bitmap methods with your own, I would carefully look at what you are trying to do - for something as complicated as image manipulation, you might be better off providing functionality next to the original methods as opposed to their replacement.